fix(track): fix silent GPX save failure + add stop friction + quit buttonmain

TrackStorage: openOutputStream null returned true (file never written).
Added IS_PENDING flag to fix Android 10-11 race where insert succeeds
but file isn't physically created yet. Added storage-mounted guard.
TrackRepository now logs save failures.

Stop tracking now requires a long press (haptic feedback) — prevents
accidental mid-sail stops from a single tap.

Quit button (top-right, tonal X) stops LocationService and calls
finishAffinity(). Prompts if a track is in progress.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

3 files changed, 70 insertions, 5 deletions

diff --git a/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt b/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
index 0309364..6263e13 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
@@ -9,6 +9,7 @@ import android.media.MediaPlayer
 import android.os.Build
 import android.os.Bundle
 import android.util.Log
+import android.view.HapticFeedbackConstants
 import android.view.View
 import android.widget.FrameLayout
 import androidx.activity.result.contract.ActivityResultContracts
@@ -51,6 +52,7 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
     private lateinit var fabRecordTrack: FloatingActionButton
     private lateinit var fabMob: FloatingActionButton
     private lateinit var fabRecenter: MaterialButton
+    private lateinit var btnQuit: MaterialButton
     private lateinit var bottomSheet: CardView
     private lateinit var bottomNav: BottomNavigationView
     private val safetyFragment = SafetyFragment().apply { setSafetyListener(this@MainActivity) }
@@ -81,6 +83,7 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
         fabRecordTrack = findViewById(R.id.fab_record_track)
         fabMob = findViewById(R.id.fab_mob)
         fabRecenter = findViewById(R.id.fab_recenter)
+        btnQuit = findViewById(R.id.btn_quit)
         bottomSheet = findViewById(R.id.instrument_bottom_sheet)
         bottomNav = findViewById(R.id.bottom_navigation)
 
@@ -89,8 +92,16 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
         setupHandlers()
         setupMap()
 
+        // Single tap starts; long press stops (requires deliberate intent mid-sail)
         fabRecordTrack.setOnClickListener {
-            if (viewModel.isRecording.value) viewModel.stopTrack() else viewModel.startTrack()
+            if (!viewModel.isRecording.value) viewModel.startTrack()
+        }
+        fabRecordTrack.setOnLongClickListener {
+            if (viewModel.isRecording.value) {
+                it.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS)
+                viewModel.stopTrack()
+                true
+            } else false
         }
 
         fabMob.setOnClickListener { onActivateMob() }
@@ -98,6 +109,8 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
         fabRecenter.setOnClickListener {
             mapHandler?.recenter()
         }
+
+        btnQuit.setOnClickListener { onQuitRequested() }
         // Observe immediately — pure UI state, not gated on GPS permission
         lifecycleScope.launch {
             viewModel.isRecording.collect { recording ->
@@ -177,6 +190,23 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
         showOverlay(fragment)
     }
 
+    private fun onQuitRequested() {
+        if (viewModel.isRecording.value) {
+            androidx.appcompat.app.AlertDialog.Builder(this)
+                .setMessage("Recording in progress. Quit and discard the current track?")
+                .setPositiveButton("Quit") { _, _ -> exitApp() }
+                .setNegativeButton("Cancel", null)
+                .show()
+        } else {
+            exitApp()
+        }
+    }
+
+    private fun exitApp() {
+        stopService(Intent(this, LocationService::class.java))
+        finishAffinity()
+    }
+
     override fun onActivateMob() {
         lifecycleScope.launch {
             LocationService.locationFlow.firstOrNull()?.let { gpsData ->
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt
index 228a484..7ef67af 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt
@@ -1,6 +1,7 @@
 package org.terst.nav.track
 
 import android.content.Context
+import android.util.Log
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 
@@ -45,7 +46,8 @@ class TrackRepository(context: Context) {
         if (summary.durationMs < 2 * 60_000L) return@withContext null
 
         _pastTracks.add(0, points)
-        storage.saveTrack(points, trackStartMs)
+        val saved = storage.saveTrack(points, trackStartMs)
+        if (!saved) Log.e("TrackRepository", "GPX save failed — ${points.size} points will be lost on restart")
         summary
     }
 
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackStorage.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackStorage.kt
index 620431c..08e1dc9 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackStorage.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackStorage.kt
@@ -5,11 +5,14 @@ import android.content.Context
 import android.os.Build
 import android.os.Environment
 import android.provider.MediaStore
+import android.util.Log
 import java.io.File
 import java.time.Instant
 import java.time.ZoneOffset
 import java.time.format.DateTimeFormatter
 
+private const val TAG = "TrackStorage"
+
 /**
  * Persists completed tracks as GPX files in the shared Documents/Nav/ folder.
  *
@@ -56,19 +59,49 @@ class TrackStorage(private val context: Context) {
     // ── API 29+ ──────────────────────────────────────────────────────────────
 
     private fun saveViaMediaStore(fileName: String, gpx: String): Boolean {
+        // Guard: external storage must be mounted before touching MediaStore
+        val storageState = Environment.getExternalStorageState()
+        if (storageState != Environment.MEDIA_MOUNTED) {
+            Log.e(TAG, "External storage not mounted (state=$storageState) — cannot save $fileName")
+            return false
+        }
+
+        // IS_PENDING marks the entry as in-progress, preventing a race condition on
+        // Android 10-11 where insert() succeeds but openOutputStream() returns null
+        // because the file hasn't been physically created on disk yet.
         val values = ContentValues().apply {
             put(MediaStore.Files.FileColumns.DISPLAY_NAME, fileName)
             put(MediaStore.Files.FileColumns.MIME_TYPE, "application/gpx+xml")
             put(MediaStore.Files.FileColumns.RELATIVE_PATH, "Documents/Nav/")
+            put(MediaStore.MediaColumns.IS_PENDING, 1)
         }
         val uri = context.contentResolver.insert(
             MediaStore.Files.getContentUri("external"), values
-        ) ?: return false
+        ) ?: run {
+            Log.e(TAG, "MediaStore insert returned null for $fileName")
+            return false
+        }
 
         return runCatching {
-            context.contentResolver.openOutputStream(uri)?.use { it.write(gpx.toByteArray()) }
+            val stream = context.contentResolver.openOutputStream(uri)
+            if (stream == null) {
+                context.contentResolver.delete(uri, null, null)
+                Log.e(TAG, "openOutputStream null for $fileName — deleted orphan entry")
+                return@runCatching false
+            }
+            stream.use { it.write(gpx.toByteArray()) }
+
+            // Clear IS_PENDING so the file is visible to other apps and file managers
+            val update = ContentValues().apply { put(MediaStore.MediaColumns.IS_PENDING, 0) }
+            context.contentResolver.update(uri, update, null, null)
+
+            Log.d(TAG, "Saved $fileName (${gpx.length} bytes) → $uri")
             true
-        }.getOrDefault(false)
+        }.getOrElse { e ->
+            Log.e(TAG, "Write failed for $fileName: ${e.message}")
+            runCatching { context.contentResolver.delete(uri, null, null) }
+            false
+        }
     }
 
     private fun loadViaMediaStore(): List<List<TrackPoint>> {